Hi,
I flew to Melb in May to pick up a new Defender and came back on the SpoT. Being early in the queue, I got stuck down stairs in the very pointy end with some other small cars. Needed about a 15 point turn to get back out as down there you come back up to the main deck the same way as you go down.
Travelling by myself for the first time on this series of ferries, I wasn't too sure of the layout for the lounge chairs and was going to take a lilo, but at the last minute didn't. - Error!
There are safety signs every where saying you can't sleep on the floor, but a lot of people do, the chairs, though comfy to sit in, are not easy to sleep in, and there are always noisy people in the lounge area.
If you are by yourself, swag it on the 5th deck I think it is, lots of empty space and benches up there.
Don't take too much stuff for the trip upstairs with you if you don't have a cabin, there is no where to store it except on your seat, which is behind locked doors, every body with a seat though has a pass card.
Seated passengers don't have access to showers either, or at least I was unable to find them. The showers were open to all on the other boats, SpoT has en-suites in the cabins.
Check the prices of various options, cheaper in winter, bit more in spring/autumn, peak season is summer.
Check prices of cabin for 4 if you have family with you, it may be cheaper to fly them down to Devonport or Launceston and travel solo as a lounge chair seat.
You will have a ball down here, distances are short, plenty of variety in the landscapes.
cheers